Demand meter and control therefor



Nov. 28, 1944. E. N. GOODMAN I DEMAND METER AND CONTROL THEREFOR 2Sheets-Sheet 1 Filed Sept. 9, 1943 Tag-.2-

I N V EN TOR. Emanuel JV Goodman Nov. 28, 1944.

E. N. GOODMA DEMAND METER AND CONTROL THEREFOR Filed Sept. 9, 1945 2Sheets-Sheet 2 IN V EN TOR. fimanuel JW G oodmcnz Patented Nov. 28, 1944UNITED STATES PATENT OFFICE 2,363,958 DEMAND METER AND CONTROL THEREFOREmanuel N. Goodman, New York, N. Y. Application September 9, 1943,Serial No. 501,639

2 Claims.

This invention relates to improvements in measuring instruments and hasparticular reference to a demand meter and control system therefor.

In demand meters for measuring electrical cur:

and then, at regular intervals of time, to return i said operatingelement to a. normal position from which itagain advances during thenext succeeding interval of time. In some known meters of this kind, asynchronous motor individual to each meter has been employed to return ithe pusher to normal. Aside from the fact that the manufacture andinstallation of such a motor in each individual meter of a system is aconsiderable added expense, these motors, although they each operate atregular intervals to restore the associated pusher to normal, do notoperate simultaneously to perform this function.

In accordance with the present invention, it is proposed to eliminatethe use of individual synchronous motors for each measuring instrument,with an attendant material reduction in the cost of manufacture, and tosimultaneously and periodically control, from a central station, therestoration of the pushers of all meters in a system by the transmissionof an impulse over a common line to energize an electromagnetic deviceat each meter which is operatively connected to the pusher of suchmeter.

Another feature is to provide an improved measuring instrument in whicha simple and practical operating-means for a demand indicator iscontrolled by the energization of an electromagnetic device toperiodically restore said operating means to a normal position withoutaffecting the advanced position of said indicator.

The inventive idea involved is capable of receiving a variety ofexpressions some of which, for purposes of illustration, are shown inthe accompanying drawings wherein Fig. 1 is a front elevation of ademand meter, broken away to show the mechanism in the rear of the faceplate and illustrating only so much of the entire mechanism of the meteras is necessary for an understanding of thepresent invention.

Fig. 2 is a sectional view taken substantially on the line 2+-2 of Fig.1.

Fig. 3 is a diagrammatic view of a circuit employed for operating aseries of measuring instruments from a central control station, and

Figs. 4, 5, and 6 are similar views illustrating other forms of circuitswhich may be employed.

It will be understood that the invention is adapted for use with varioustypes of measuring instruments and that the watthour demand meter shownin Figs. 1 and 2 is employed merely to illustrate an adaptation in whichan integrating mechanism including a plurality of registering dials IDare mounted upon the face plate II, and wherein the indicator I2 ismovable rotatively over the graduated dial I3 fixed to said face plateabove said dials i0. Said integrating mechanism is operated from theusual shaft M of the meter which has a worm l5 thereon for driving thegear I6. This latter gear is mounted on the shaft l'l having the wormsl8 and IS, the former of which engages the gear 20 of the usual train ofgearing (not shown) employed to operate the elements of the integratingmechanism. This type of meter has a shaft 2| rotatably mounted betweenbearings 22 and carries, at its end adjacent'the face plate I l, theindicator operating element or pusher 23 in the form of an arm. Theindicator I2 is rotatably mounted at 25 in alinement with the axis ofthe shaft 2|, and its inner bent end projects through an opening 25 inthe face plate II and carries a small roller 26 adapted to be contactedby the pusher 23 as the latter is rotated in a clockwise direction(Fig. 1) to advance the indicator I2 over the graduated dial l3... As iscustomary, this advance of the indicator is accomplished during apredetermined interval of time and at the end of such interval thepusher 23 is returned to normal, leaving the indicator in its advancedposition so as to register the maximum demand for said interval. Duringthe next succeeding interval of time, the pusher may or may not reachthe roller 26 and in the former event the indicator is advanced again,and at the termination of a period of time, such as thirty days, thethen advanced position of the indicator will register the maximumaverage demand on the meter for said period.

The shaft 2| is driven from the worm H! on the shaft I! through themedium of a gear 21 meshing with said worm and mounted on a shaft 28which also carries another gear 29 meshed with the gear 30 looselymopnted on the shaft 2|.

Said gear 30 is supported on the shaft by a collar 3| engaged by thecoil spring 32 on said shaft so as to exert a yielding pressure uponsaid gear. Fixed on the shaft 2| is a plate 33 and interposed betweenthe latter and the gear 39 is a friction disc 34 which constitutes aclutch between said gear and plate to rotate the latter and consequentlythe shaft 2! to advance the pusher 23 from its normal position to theother extremity of its movement. In the normal position of the pusher, apin 35 on the plate 33 contacts a light spring stop 36 mounted on theframework of the meter, and this stop pin limits the movement of thepusher from an advanced to the normal position thereof, as will appearin the course of the description. At the extremity of its advancedmovement, if such point is reached during the operation of the meter,the pusher forces the roller 26 on the indicator against the stop pin 31and, in this event, further rotation of the gear 30,

due to continuing operation of the shaft II, will pear, thecounter-clockwisev rotation'of the shaft 2| during the instant ofrestoration is independ-. ent of the gear which may continue 'to berotated by the gear 29. With the latter gear 'being driven at theinstant the pusher is returned to normal, said pusher will immediatelystart its advancing movement since the gear 30 will have then againbecome effective to drive the plate 33 through the clutch disc 34. I

For the purpose of effecting the returnmovement of the pusher 23 tonormal position, it is proposed to fix on the shaft 2| a small gear 38with which is meshed a large segmental gear 39 mounted upon the shaft40. As the shaft 2| is rotated clockwise, the gear 38 turns the gear 39in the opposite direction about the shaft without effect, but when themovement of the latter gear is reversed by the energization of asuitable electromagnetic device 4|, the gear 38 and plate. 33., andconsequently the shaft 2|, will be rotated counter-clockwise andindependently of the gear 39 until the pin on the plate contacts thespring stop 36, whereupon the pusher will again be in normal positionand ready for its next advancement toward theindicator- |2 which hadremained in the position to which it had'been advanced by the previousoperation of the pusher. The electromagnetic device 4| is energized, inaccordance with the invention, at regular intervals by an impulsetransmitted thereto from a central control station and when so energizedits armature 42 is attracted. Said armature is pro.- vided with anextension 43, that terminates in a spring contact piece 44 so positionedthat when the armature is attracted against the tension of its returnspring 45, the contact 44 will engage the shoe 46 carried by the gear39. adjacent its shaft and, as a consequence, said gear will be turnedto rotate the shaft 2|, through .the gear 38, in a counter-clockwisedirection to 1 8? store the pusher 23 to its normal position, whereuponthe device 4| becomes deenergized andits armature, and the parts 43 and44 carried thereby, are also returned to normal by the spring 45. When anumber of meters such as described are included in a system it isdesirable, for reasons of practicability, that the electromagnetsthereof be simultaneously energized at predetermined intervals and, forthis purpose, the invention further contemplates a circuit in which allthe meters in the'system are controlled from a central station by thetransmission'therefrom of an impulse which will energize theelectromagnets 4| of all the meters to restore the associated pushers tonormal "at one and the same time. As shown in Fig. 3, all the meters areconnected to the line conductors 41 le'ading'fro'm the central controlstation'48 at which is located a time controlled switch conventionallyshown and indicated by the numeral 49. In this circuit, which may besupplied with either alternating or direct current, an auxiliaryconductor is employed that is connected tothe winding of eachelectromagnet 4| and in which the normally open contacts 5| of theswitch 49 are included. Thus, when the said switch, which may be 0p- Ierated by a synchronous motor or other suitable normal positions.

In Fig. 4, the adaptation of the central control to a 3-phase, 4-wiresystem is shown. In this embodiment, the various electromagnets in thesystern are so designed that the normal voltage of an alternatingcurrent installation will not energize the magnets against their springtension, but when a low voltage direct current is impressed upon thecircuit of saidmagnets they will energize to restore their respectivepushers. The eleotromagnets in this circuit may also be designed with amagnetic leakage-shunt so that the pull of the magnets becomes ample toenergize the magnets and thus restore the pushers. Therefore, at thecontrol station a low voltage, self-excited direct current generatorisconnected to the neutral, rounded conductor 52 of the 4.- wire system,with the armature 53. of said generator normally short circuited by theshunt 54 and the jumper 55 the latter of which is engaged by the timecontrolled switch generally indicated; by the numeral 56 and operated ina manner similar to the switch 49. When said switch isv operated atpredetermined and regular intervals, it is thrown to the position whereit engages the terminals of the generator shunt field 51, thusmomentarily connecting said field to the line circuit to energize allthe electromagnets therein, after which said switch is returned to itsnormal position. While, according to the illustration, the armature 53remains in the circuit at all times, it is not necessary to keep thegenerator running continuously, since it is quite possibleto control thesam so that it. may be started just 'prior'to the time when the switch56 is due to be operated.

In the arrangement illustrated in Fig. 5, a shunt wound generator at thecontrol station is conventionally shown in which the armature 58 is incircuit with the grounded, neutral conductor 52, and the generator,together with its shunt field 59, is normally shorted by the timecontrolled switch 60. As said switch is operated at predetermined andregular intervals, it moves through the resistance 6| to its dottedli'nep'osition at which time the magnets 4| of the system are energizedand said switch is then moved slowly back to its normal position.

When a direct current system is employed, as in Fig. 6, theelectromagnets should each have in series therewith a condenser 62, andwhen the capacity of the condenser is properly proportioned to theinductance of the magnet'coil, a low voltage alternating current inseries with the direct current will, at the proper time intervals,energize the magnet to restore its pusher. The alternating current maybe of a standard frequency and supplied by a step-down transformer thelow voltage secondary 64 of which-is in se: ries with one of the lineconductors 63. A short circuit 65 for the secondary is normally closedby the time controlled switch 66, but when-the latter is thrown, atpredetermined intervals, it connects the primary 6! of the transformerin the circuit to thereby impress upon the direct current line analternating current supplied to the primary over the conductors 68 whichare connected to a suitable source.

It is to be further noted that when an auxiliary conductor is used as inFig. 3, in an alternating current system having transformers between thepower plant and the service lines, the time controlled switch may belocated either on the service side of the transformers or in the powerplant, in which case a separate transformer used. The secondary voltageof this transformer may be standard or a low voltage may be used tooperate the magnets of the demand meters.

What is claimed is:

l. In a metering system, a three phase, four wire circuit including agrounded neutral conductor, a plurality of measuring instruments in saidcircuit and each including an indicator operable in accordance withvalues of a quantity being measured, means movable from a normalposition to so operate said indicator, an impulseresponsive element ateach measurin instrument operatively connected to said operating means,a control station,.a low voltage direct current generator at saidcontrol station having its armature normally short circuited andpermanently connected to said neutral conductor, a shunt field for saidgenerator, and a switch normally short circuiting said armature andperiodically operated to open said short and connect said shunt field tosaid armature whereby to transmit an impulse over said conductor to saidresponsive elements to restore said indicator operating means at eachinstrument to normal position.

2. In a metering system in which direct current impulses aresuperimposed upon a three phase, four wire circuit including a neutralground conductor to operate an electro-responsive device permanentlyconnected to said circuit and the neutral conductor thereof, thecombination of a low voltage direct current generator having itsarmature permanently connected to said grounded conductor and furtherhaving a shunt field, means to normally short circuit said armature and,means to open said short circuit and connect said shunt field to saidarmature whereby to superimpose a direct currentimpulse upon saidcircuit and thereby energize said electro -responsive device.

EMANUEL N. GOODMAN.

